Satellites help tackle landfill methane leaks

With methane’s heat-trapping power being 28 times stronger than carbon dioxide over a century and 80 times more powerful in 20 years, commitments to reduce emissions are at the top of the international agenda, including the Global Methane Pledge, which aims for a 30% reduction by 2030.

Landfill sites are a potential source, accounting for more than 10% of human-caused methane emissions.

Mapping Methane at Landfill Sites
To test how space-based detection can help detect leaks and then assess whether repairs are working, the European Space Agency teamed up with leading scientists and managers of the Las Dehesas landfill (Madrid City Council and its operating company, Urbesar) to conduct a real-world case study in Spain, setting a new standard for methane tracking in the waste sector.

From spring 2025 onwards, concurrent measurements of methane emissions have been collected using ground surveys, sensor-equipped aircraft and satellites to assess a landfill site 18 km south-east of Madrid.

The research team led by Harjinder Sembhi at the University of Leicester conducted a high-resolution assessment of the Las Dehesas landfill site and the surrounding area as part of ongoing work within and with ESA’s climate change initiative MEDUSA Project.

Data from ESA’s Sentinel-5P mission provide a comprehensive view of methane across entire regions, and high-resolution instruments like GHGSat – a Canadian emissions-technology provider leveraging satellites and aircraft – can use this information to zoom in on the exact sources.

In May 2025, GHGSat’s 25 × 25 m sensor, capable of identifying leaks as small as ~100 kg per hour, captured detailed snapshots of a methane plume over a Madrid landfill. At the same time, research aircraft equipped with similar methane-detecting instruments flew low over the site, producing ultra-fine, 1-meter-resolution maps capable of pinpointing even small leaks of up to only 5 kilograms per hour.

The survey was repeated in September and October to assess the impact of summer repair work, which included maintenance of gas-collection wells and pipelines, and adjustments to the way the landfill’s surface was managed.

“By combining the frequency of high-resolution satellite measurements with the targeted visualization of high-resolution airborne measurements, we are able to gain an unprecedented understanding of how landfill methane behaves. This level of insight empowers operators to target solutions more effectively and ultimately deliver meaningful emissions reductions,” said Dan Wicks, UK Managing Director, GHGSat.

“We had a very clear objective – to use satellite and aircraft measurements to detect leaks and guide remediation activity on the ground,” explains Dr. Aben, who led extensive efforts to evaluate methane data products obtained from a wide range of satellites as part of the MEDUSA project.

“The methane maps we were able to produce provide a way to engage and directly help ground operations and translate observations into real-world action.”

Collaboration key to climate action

Key to the success of the study is the openness and strong collaboration between the Madrid City Council and the Las Dehesas landfill operators on the Valmendigómez Technology Park, and research partners including ESA, GHGSat, the University of Leicester in the UK, the Space Research Organization Netherlands (SRON), the International Methane Emissions Observatory (IMEO), and the Danish Technical University (DTU).

The Director General of the Valdemingómez Technology Park, María José Delgado, expresses the Madrid City Council’s desire to collaborate on this innovative project, which enables the comparison of different technologies to detect fugitive emissions of biogas from landfills, thereby improving environmental control in landfill management and contributing to the fight against climate change.

Sharing details of site activity and periodic ground monitoring with airborne observations provided important context to the science team. In turn, the researchers’ quick analysis and mapping helped identify leak locations and persistence to guide the landfill operator’s remediation activity.

By focusing on the waste sector, the case studies aim to inform satellite-guided pathways to reduce or avoid emissions, mirroring successes targeting oil and gas facilities. Although it is difficult to reduce emissions from landfills, unlike industrial facilities, this practice indicates that the potential exists.

Dr Sembhi, of the University of Leicester, said, “In many cases, the operator was able to investigate leak locations because we were circulating data reports and prioritizing action.

“Landfill gas production is generally of a widespread nature, influenced by dynamic and changing site activity as well as the potential impact of prevailing weather and ground conditions.

“Using these new observations, site information and local meteorological data we are investigating the factors influencing the occurrence and persistence of leaks. Improved understanding will help better measure emissions and should inform practical steps to reduce or avoid emissions.

Previous satellite-based surveys of methane emissions from landfill sites have found little correlation with reported or modeled emission estimates at the facility scale, leaving large uncertainties in the current understanding.

Dr. Sembhi said, “The opportunity to work with operators can help us optimize the use of remote sensing to improve monitoring. This will allow us to identify the reasons for the differences between satellite-based and facility-calculated methane emissions and achieve real-world emissions reductions.”

Timon Hammel, ESA’s Mission Manager for Atmospheric Missions, said, “Satellites can detect and quantify methane emissions faster and with far greater precision than ever before. Using this new scientific insight, the waste sector has the potential to accelerate effective action on the ground, providing real-world mitigation to support sector, national and global efforts to limit warming to 1.5°C in line with the Paris Agreement. Does.”

Results from the field study are expected to be available in early 2026, including evaluation of therapeutic activity effectiveness currently underway.

Dr. Sembhi said, “Detection is only half of the coin. We are assessing how robust and long-lasting the treatment is in terms of preventing leaks. Once completed we will advance the knowledge of monitoring and quantifying waste field emissions while laying the groundwork for satellite-driven landfill methane monitoring to support cities and waste managers in cutting emissions.”